/*
 * Copyright (c) 2022 wanglinchao 
 * Licensed under the Apache License,Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
export class EventBus {
    constructor(){
        this.eventList ={}
    }

//    注册事件 字符串和回调
    on(event,fn){
        let eventList = this.eventList[event]
        eventList?eventList.push(fn):this.eventList[event] = [fn]//如果事件存在，则把回调函数放进去，否则新建出来这个事件的字段装入传进来的函数

    }

    emit(event,...arg){
        this.eventList[event]&&this.eventList[event].forEach(fn =>{
            fn(...arg)
        })

    }
}